1. Field of the Invention
This invention relates to electrical safety protection, and in particular, it relates to a power plug or receptacle with a ground-fault circuit interrupter (GFCI) device utilizing a relay mechanism to reset the GFCI device.
2. Description of the Related Art
Currently, to ensure safety in using electrical household appliances, the input side of the household appliances is usually provided with a power plug or receptacle having a ground-fault circuit interrupter (GFCI) device. Traditional GFCI devices have utilized mechanical reset mechanisms, wherein after reset, in an electrically disconnected state, the GFCI device remains in a reset state, i.e., the switch between the input and output terminals remains closed. However, at this state, if the hot wire of the input terminal is provided with electrical power, then the output terminal of the device will still have power, which presents a personal safety danger to the user.
Some other traditional GFCI devices utilize relay reset mechanisms but the spacing of the switch contacts between the electrical conductors of the input and output conducting path cannot be too large, otherwise the switch cannot be electromagnetically pulled to close. To solve this problem some existing GFCI devices with relay reset mechanisms apply larger electrical current to the relay, so that even switches with large spacing may be electromagnetically pulled to close. But when these types of GFCI devices are powered on for an extended period of time, the coils of the relays will heat up significantly, seriously increasing the risk of fire hazard.
Therefore, it is desirable to provide a new relay reset circuit design for GFCI devices, which can ensure that even when one of the input terminals is provided with electrical power, the output or load terminals still has no power, and which can also ensure that the switch can be reliably pulled to close electromagnetically while the spacing of the switch contacts can still be increased, so that the relay mechanism can function normally and the personal safety of the users are protected.